I try to set restriction to a page using "public access" from page properties. After selecting "Single User protection" and setting login and error nodes, I simlpy get the following error.

The parameter 'username' must not be empty.
Parameter name: username

and in the member section I see automatically created __umbracoRole_ in member group and _umbracoSystemDefaultProtectType as member type.

I would like to know what might have caused it and hopefully get some feedback about it.